This invention is directed to an encapsulated quantum dot light emitting diode (QD-LED), and in particular, an encapsulation structure and method of manufacture which promotes a beneficial aging effect in the quantum dot light emitting diode.
Quantum dot light emitting diodes are well known in the art. The basic structure for a bottom-emitting device is a glass substrate and a QD-LED stack which includes a quantum dot light emitting layer, nanoparticle layers and the like. The QD-LED stack is made of sensitive materials and therefore needs to be protected from the environment. As known in the art, protective encapsulation layers are disposed over the sensitive materials as a protective cover. This encapsulation has taken the form of a curable resin.
Loctite 349 curable resin has been used to encapsulate organic LEDs (OLED). Loctite 349 is just one of many curable resins utilized to encapsulate OLED, and has not been used to encapsulate QD-LEDs which are made of inorganic or a combination of inorganic and organic materials. Some QD-LEDs exhibit a “positive aging effect” in which the various efficiencies (current, power or external quantum efficiencies) improve over time. The positive aging effect can be contrasted to degradation of QD-LED's to lower brightness and lower efficiencies, sometimes called the negative aging effects. However, no such positive aging effect has been observed in OLEDs using Loctite 349.
Because the prior art structures do not promote the positive aging effect as defined above, a structure and/or a method of manufacture which further promotes the aging effect is desired.